Methods of forming pmos and nmos finfet devices on cmos based integrated circuit products

ABSTRACT

One illustrative method disclosed herein includes, among other things, forming first and second fins, respectively, for a PMOS device and an NMOS device, each of the first and second fins comprising a lower substrate fin portion made of the substrate material and an upper fin portion that is made of a second semiconductor material that is different from the substrate material, exposing at least a portion of the upper fin portion of both the first and second fins, masking the PMOS device and forming a semiconductor material cladding on the exposed upper portion of the second fin for the NMOS device, wherein the semiconductor material cladding is a different semiconductor material than that of the second semiconductor material. The method also including forming gate structures for the PMOS FinFET device and the NMOS FinFET device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Generally, the present disclosure relates to the manufacture of FETsemiconductor devices, and, more specifically, to various methods offorming PMOS and NMOS FinFET devices on CMOS based integrated circuitproducts.

2. Description of the Related Art

In modern integrated circuits, such as microprocessors, storage devicesand the like, a very large number of circuit elements, especiallytransistors, are provided on a restricted chip area. Transistors come ina variety of shapes and forms, e.g., planar transistors, FinFETtransistors, nanowire devices, etc. The transistors are typically eitherNMOS (NFET) or PMOS (PFET) type devices wherein the “N” and “P”designation is based upon the type of dopants used to create thesource/drain regions of the devices. So-called CMOS (Complementary MetalOxide Semiconductor) technology or products refers to integrated circuitproducts that are manufactured using both NMOS and PMOS transistordevices. Irrespective of the physical configuration of the transistordevice, each transistor device comprises laterally spaced apart drainand source regions that are formed in a semiconductor substrate, a gateelectrode structure positioned above the substrate and between thesource/drain regions, and a gate insulation layer positioned between thegate electrode and the substrate. Upon application of an appropriatecontrol voltage to the gate electrode, a conductive channel region formsbetween the drain region and the source region and current flows fromthe source region to the drain region.

A conventional FET is a planar device wherein the entire channel regionof the device is formed parallel and slightly below the planar uppersurface of the semiconducting substrate. To improve the operating speedof planar FETs, and to increase the density of planar FETs on anintegrated circuit product, device designers have greatly reduced thephysical size of planar FETs over the past decades. More specifically,the channel length of planar FETs has been significantly decreased,which has resulted in improving the switching speed and in loweringoperation currents and voltages of planar FETs. However, decreasing thechannel length of a planar FET also decreases the distance between thesource region and the drain region. In some cases, this decrease in theseparation between the source and the drain makes it difficult toefficiently inhibit the electrical potential of the source region andthe channel from being adversely affected by the electrical potential ofthe drain. This is sometimes referred to as a so-called short channeleffect, wherein the characteristic of the planar FET as an active switchis degraded.

In contrast to a planar FET, there are so-called 3D devices, such as anillustrative FinFET device, which is a three-dimensional structure. FIG.1A is a perspective view of an illustrative prior art FinFETsemiconductor device 10 that is formed above a semiconductor substrate12 wherein the fins 14 of the device 10 are made of the material of thesubstrate 12, e.g., silicon. The device 10 includes a plurality oftrenches 13, three illustrative fins 14, a gate structure 16, a sidewallspacer 18 and a gate cap layer 20. An isolation material 17 provideselectrical isolation between the fins 14. The gate structure 16 istypically comprised of a layer of insulating material (not separatelyshown), e.g., a layer of high-k insulating material, and one or moreconductive material layers that serve as the gate electrode for thedevice 10. The fins 14 have a three dimensional configuration: a heightH, a width W and an axial length L. The axial length L corresponds tothe direction of current travel in the device 10 when it is operational.The portions of the fins 14 covered by the gate structure 16 are thechannel regions of the FinFET device 10. The portions of the fins 14that are positioned outside of the spacers 18 will become part of thesource/drain regions of the device 10.

In the FinFET device 10, the gate structure 16 encloses both sides andthe upper surface of the fins 14 to form a tri-gate structure so as touse a channel having a three-dimensional structure instead of a planarstructure. In some cases, an insulating cap layer, e.g., siliconnitride, is positioned at the top of the fins 14 and the FinFET deviceonly has a dual-gate structure (sidewalls only). Unlike a planar FET, ina FinFET device, a channel is formed perpendicular to a surface of thesemiconducting substrate so as to increase the drive current perfootprint of the device. Also, in a FinFET, the improved gate controlthrough multiple gates on a narrow, fully-depleted semiconductor finsignificantly reduces the short channel effects. When an appropriatevoltage is applied to the gate electrode 16 of a FinFET device 10, thesurfaces (and the inner portion near the surface) of the fins 14, i.e.,the vertically oriented sidewalls and the top upper surface of the fin,form a surface inversion layer or a volume inversion layer thatcontributes to current conduction. Accordingly, for a given plot space(or foot-print), FinFETs tend to be able to generate significantlyhigher drive current than planar transistor devices. Additionally, theleakage current of FinFET devices after the device is turned “OFF” issignificantly reduced as compared to the leakage current of planar FETs,due to the superior gate electrostatic control of the “fin” channel onFinFET devices. In short, the 3D structure of a FinFET device is asuperior MOSFET structure as compared to that of a planar FET,especially in the 20 nm CMOS technology node and beyond.

Device manufacturers are under constant pressure to produce integratedcircuit products with increased performance and lower production costsrelative to previous device generations. Thus, device designers spend agreat amount of time and effort to maximize device performance whileseeking ways to reduce manufacturing costs and improve manufacturingreliability. As it relates to 3D devices, device designers have spentmany years and employed a variety of techniques in an effort to improvethe performance, capability and reliability of such devices. Devicedesigners are currently investigating alternative semiconductormaterials, such as SiGe, Ge and III-V materials, to manufacture FinFETdevices, which are intended to enhance the performance capabilities ofsuch devices, e.g., to enable low-voltage operation without degradingtheir operating speed.

FIG. 1B is a perspective view of an illustrative prior art FinFETsemiconductor device 10, wherein the overall fin structure of the deviceincludes a substrate fin portion 14A and an alternative fin materialportion 14B. As with the case above, the substrate fin portion 14A maybe made of silicon, i.e., the same material as the substrate, and thealternative fin material portion 14B may be made of a material otherthan the substrate material, for example, silicon-germanium,substantially pure germanium, III-V materials, etc. As noted above, theuse of such alternative fin materials improves the mobility of chargecarriers in the device.

However, the integration of such alternative materials on siliconsubstrates (the dominant substrates used in the industry) is non-trivialdue to, among other issues, the large difference in lattice constantsbetween such alternative materials and silicon. That is, with referenceto FIG. 1B, the lattice constant of the alternative fin material portion14B of the fin 14 may be substantially greater than the lattice constantof the substrate fin portion 14A of the fin 14. As a result of thismismatch in lattice constants, an unacceptable number of defects may beformed or created in the alternative fin material portion 14B. As usedherein, a “defect” essentially refers to a misfit dislocation at theinterface between the portions 14A and 14B of the fin 14 or threadingdislocations that propagate through the portion 14B on the fin 14 atwell-defined angles.

With respect to forming such lattice-constant-mismatched materials onone another, there is a concept that is generally referred to as the“critical thickness” of a material. The term “critical thickness”generally refers to materials that are in one of three conditions, i.e.,so-called “stable,” “metastable” or “relaxed-with-defects” conditions.These three conditions also generally reflect the state of the strain onthe material. That is, a stable material is in a fully-strainedcondition that is 100% strained in at least one crystalline plane of thematerial, a relaxed-with-defects material is a material that has zerostrain in all crystalline planes, and a metastable material is strainedto a level that is above zero strain but less than 100% strained in atleast one crystalline plane of the metastable material. In general, afully-strained (stable) material or a partially-strained (metastable)material will have fewer defects than a fully relaxed, unstrainedmaterial.

FIG. 1C is a graph taken from an article entitled “Silicon-GermaniumStrained Layer Materials in Microelectronics” by Douglas J. Paul thatwas published in Advanced Materials magazine (11(3), 101-204 (1999)).FIG. 1C graphically depicts these three conditions for silicon germaniummaterials (Si_(1-x)Ge_(x); x=0-1). The vertical axis is the criticalthickness in nanometers. The horizontal axis is the concentration ofgermanium in the silicon germanium material. At the leftmost point onthe horizontal axis is pure silicon (Ge concentration equals 0.0). Atthe rightmost point on the horizontal axis is pure germanium (Geconcentration equals 1.0). The two curves R and S define the stable,metastable and relaxed-with-defects regions for silicon germaniummaterials having differing germanium concentration levels. Above and tothe right of curve R are materials that are in a relaxed condition withdefects present in the material. Below and to the left of the curve Sare materials that are in the stable or fully strained condition wherethere are little or no defects present in the material. The regionbetween the two curves R and S defines the region where materials are inthe metastable condition. The graph reflects the critical thickness ofvarious materials when they are grown in an unconfined growthenvironment, e.g., when growing a substantially planar alternativesemiconductor film or layer on the entire upper surface of a siliconsubstrate.

To add more precision to the terminology regarding critical thickness,the term “stable critical thickness” will be used herein and in theattached claims to refer to a maximum thickness of a material at whichit may be formed in a substantially defect-free and “fully-strained”condition above a substrate material in an unconfined growthenvironment.

Additionally, as used herein and in the attached claims, the term“metastable critical thickness” will be used to refer to a maximumthickness of a material at which it may be formed in a metastablecondition above a substrate material, i.e., in an unconfined growthenvironment. As noted above, a material that is in the metastablecondition is a material that has experienced some degree ofstrain-relaxation, but still remains strained to some degree (i.e.,1-99% strained but not 100% strained) in one crystalline plane of themetastable material such that defects are not typically formed in themetastable material itself. However, a metastable material may or maynot have some amount of defects at the interface between the alternativematerial and a silicon substrate depending upon the amount of strainrelaxation that has happened to the material.

With reference to FIG. 1C, a layer of pure germanium (Ge concentrationequal to 1.0) may be in the stable and fully strained condition at athickness up to about 1-2 nm (point CT1) and it may be in a metastablecondition for thicknesses between about 2-4 nm (point CT2). Above athickness of about 4 nm, a layer of pure germanium will be in therelaxed-with-defects condition. In contrast, a layer of silicongermanium with a 50% concentration of germanium may be in the stable andfully strained condition at thicknesses up to about 4 nm (point CT3) andit may be in a metastable condition for thicknesses between about 4-30nm (point CT4). Above a thickness of about 30 nm, a layer of silicongermanium with a 50% concentration of germanium will be in therelaxed-with-defects condition. A material that is in therelaxed-with-defects condition is a material that contains visibledefects that are indicative that the material has relaxed to the pointwhere defects have been formed in the material.

As another example, a substantially pure layer of germanium (Geconcentration equal to 1.0) may have a maximum stable critical thicknessof about 1-2 nm when formed on a silicon substrate, i.e., in anunconfined growth environment. A substantially pure layer of germaniumformed to a thickness of 1-2 nm or less would be considered to be astable, fully-strained layer of germanium. In contrast, a layer ofsilicon germanium with a concentration of germanium of about fiftypercent (SiGe_(0.5)) may have a maximum stable critical thickness ofabout 4 nm and still be substantially free of defects, i.e., in a stablecondition. However, such a layer of germanium or silicon germanium wouldno longer be considered to be a stable material if grown beyond theirrespective maximum stable critical thickness values. When such a layerof material is grown to a thickness that is greater than its maximumstable critical thickness but less than its maximum metastablethickness, it is considered to be a metastable material that would startexperiencing some degree of relaxation, i.e., there will be some degreeof strain relaxation along one or more of the crystalline planes of thematerial and there may or may not be some defects present at or near theinterface between the alternative fin material and the substrate fin.Thus, in general, the formation of stable, fully-strained, substantiallydefect-free alternative materials on silicon is limited to very thinlayers of the alternative materials.

One of the proposed approaches for the formation of alternativematerials for FinFET devices will now be discussed with reference toFIGS. 1D-1H, which are cross-sectional views of the fins taken in a gatewidth direction of the device 10. As shown in FIG. 1D, the initial finstructures 14 are formed in the substrate 12 by performing an etchingprocess through a patterned etch mask 15. FIG. 1E depicts the device 10after the layer of insulating material 17 was deposited in the trenches13 and one or more chemical mechanical polishing (CMP) processes wereperformed to remove the etch mask 15 and excess amounts of the layer ofinsulating material 17. These operations expose the upper surface of thefins 14. Next, as shown in FIG. 1F, a timed recessing etching processwas performed to remove a portion of the initial fins 14 (now denoted asfins 14A) such that they have a recessed upper surface 14R. Thereafter,as shown in FIG. 1G, the alternative fin material 14B is grown on therecessed fin structures by performing a selective epitaxial depositionprocess. FIG. 1H depicts the device after a recess etching process wasperformed on the layer of insulating material 17 such that it has arecessed upper surface 17R that exposes the desired amount of thealternative fin material 14B. At the point of processing depicted inFIG. 1H, traditional manufacturing processes are then performed to formthe gate structure 16, gate cap layer 20 and sidewall spacers 18.

Another prior art technique for forming fins made of alternativesemiconductor materials involves the formation of one or more so-calledSRB (strained relaxed buffer) layers on the silicon substrate (prior tofin-formation) or on the recessed silicon fins prior to formation of thechannel semiconductor material, such as a material containing a highconcentration of germanium or substantially pure germanium. For example,a germanium channel material formed on an SRB layer having a relativelylow percentage of germanium, e.g., 25% or less, can provide substantialband offset isolation for PMOS devices. However, band offset isolationis not possible for an NMOS device using the same SRB layer due to thedifferent nature and composition of an NMOS device and a PMOS device.This is problematic for many integrated circuit products that aremanufactured using CMOS technology, i.e., using both NMOS and PMOSdevices. The formation of separate SRB layers for NMOS and PMOS deviceswould increase processing complexity and costs.

It is also known in the prior art to form semiconductor materialcladding on the fin of a FinFET device. FIG. 1I is a cross-sectionalview of a FinFET 30 device taken through the gate structure 32 in a gatewidth direction of the device 30. Also depicted are a semiconductorsubstrate 31, a fin 33, a recessed layer of insulating material 35 and agate cap layer 39. The gate structure 32 is typically comprised of alayer of gate insulating material 30A, e.g., a layer of high-kinsulating material (k-value of 10 or greater) or silicon dioxide, andone or more conductive material layers (e.g., metal, metal alloy, metalstack and/or polysilicon) that serve as the gate electrode 30B for thedevice 30. In the device 30, the cladding material 34 is the primarycurrent carrying portion of the channel region when the device 30 isoperational. Typically, with respect to current day technology, thecladding material 34 may have a thickness of about 2-3 nm. The claddingmaterial 34 is typically an epi semiconductor material, such as silicongermanium, that is formed on the fin 33 by performing known epideposition processes.

One process flow that is typically performed to form the illustrativeFinFET device 30 with the cladding material 34 positioned on the fin 33is as follows. First, a plurality of trenches 37 were formed in thesubstrate 31 to define the initial fins 33 (only one fin is shown inFIG. 1I). After the trenches 37 are formed, a layer of insulatingmaterial 35, such as silicon dioxide, was formed so as to overfill thetrenches 37. Thereafter, a CMP process was performed to planarize theupper surface of the insulating material 35 with the top of the fins 33(or the top of a patterned hard mask). Thereafter, a recess etchingprocess was performed to recess the layer of insulating material 35between adjacent fins 33 so as to thereby expose the upper portion ofthe fin 33. At this point, an epitaxial deposition process was performedto form the cladding material 34 on the exposed portion of the fin 33.Additional steps are then performed to complete the fabrication of thedevice, i.e., gate formation, sidewall spacer formation, epi materialgrowth in the source/drain regions of the device, etc.

The present disclosure is directed to various methods of forming PMOSand NMOS FinFET devices on CMOS based integrated circuit products thatmay solve or reduce one or more of the problems identified above.

SUMMARY OF THE INVENTION

The following presents a simplified summary of the invention in order toprovide a basic understanding of some aspects of the invention. Thissummary is not an exhaustive overview of the invention. It is notintended to identify key or critical elements of the invention or todelineate the scope of the invention. Its sole purpose is to presentsome concepts in a simplified form as a prelude to the more detaileddescription that is discussed later.

Generally, the present disclosure is directed to various methods offorming PMOS and NMOS FinFET devices on CMOS based integrated circuitproducts. One illustrative method disclosed herein includes, among otherthings, forming a first fin for a PMOS device and a second fin for anNMOS device, each of the first and second fins comprising a lowersubstrate fin portion made of the substrate material and an upper finportion that is made of a second semiconductor material that isdifferent from the substrate material, exposing at least a portion ofthe upper fin portion of both of the first and second fins, masking thePMOS device and forming a semiconductor material cladding on the exposedupper portion of the second fin for the NMOS device, wherein thesemiconductor material cladding is a different semiconductor materialthan that of the second semiconductor material. In this embodiment, themethod also includes forming a PMOS gate structure for the PMOS FinFETdevice and forming an NMOS gate structure for the NMOS FinFET device.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be understood by reference to the followingdescription taken in conjunction with the accompanying drawings, inwhich like reference numerals identify like elements, and in which:

FIG. 1A depicts an example of prior art FinFET devices wherein the finsfor the device are comprised of the substrate material;

FIG. 1B depicts an example of prior art FinFET devices wherein the finsfor the device are comprised of an alternative fin material formed abovea substrate fin;

FIG. 1C is an illustrative example of a graph that depicts the conditionof alternative materials when formed in an unconfined growthenvironment;

FIGS. 1D-1H depict one illustrative prior art process flow for formingalternative fin materials on FinFET devices;

FIG. 1I depicts one illustrative process flow for forming asemiconductor material cladding on a fin for a FinFET device;

FIGS. 2A-2H depict various illustrative novel methods disclosed hereinfor forming PMOS and NMOS FinFET devices on CMOS based integratedcircuit products; and

FIGS. 3A-3I depict yet other illustrative novel methods disclosed hereinfor forming PMOS FinFET devices and multiple NMOS FinFET devices withdifferent structural configurations and different performancecharacteristics.

While the subject matter disclosed herein is susceptible to variousmodifications and alternative forms, specific embodiments thereof havebeen shown by way of example in the drawings and are herein described indetail. It should be understood, however, that the description herein ofspecific embodiments is not intended to limit the invention to theparticular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

Various illustrative embodiments of the invention are described below.In the interest of clarity, not all features of an actual implementationare described in this specification. It will of course be appreciatedthat in the development of any such actual embodiment, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure.

The present subject matter will now be described with reference to theattached figures. Various structures, systems and devices areschematically depicted in the drawings for purposes of explanation onlyand so as to not obscure the present disclosure with details that arewell known to those skilled in the art. Nevertheless, the attacheddrawings are included to describe and explain illustrative examples ofthe present disclosure. The words and phrases used herein should beunderstood and interpreted to have a meaning consistent with theunderstanding of those words and phrases by those skilled in therelevant art. No special definition of a term or phrase, i.e., adefinition that is different from the ordinary and customary meaning asunderstood by those skilled in the art, is intended to be implied byconsistent usage of the term or phrase herein. To the extent that a termor phrase is intended to have a special meaning, i.e., a meaning otherthan that understood by skilled artisans, such a special definition willbe expressly set forth in the specification in a definitional mannerthat directly and unequivocally provides the special definition for theterm or phrase.

The methods disclosed herein may be employed in manufacturing N-typedevices and P-type devices, and the gate structure of such devices maybe formed using either so-called “gate-first” or “replacement gate”(“gate-last” or “gate-metal-last”) techniques. As will be readilyapparent to those skilled in the art upon a complete reading of thepresent application, the present method is applicable to a variety ofdevices, including, but not limited to, logic devices, memory devices,etc. With reference to the attached figures, various illustrativeembodiments of the methods and devices disclosed herein will now bedescribed in more detail.

FIGS. 2A-2H depict various illustrative novel methods of forming PMOSand NMOS FinFET devices on CMOS based integrated circuit products. Ofcourse, the integrated circuit depicted herein may also include othertypes of FET devices, such as planar FETs. With reference to FIG. 2A,the product 100 depicted herein will be formed above a semiconductorsubstrate 102 comprised of a semiconductor material, such as, forexample, a bulk silicon substrate. Thus, the terms “substrate,”“semiconductor substrate” or “semiconducting substrate” should beunderstood to cover all semiconductor materials.

FIG. 2B depicts the product 100 after one or more etching processes,e.g., anisotropic etching processes, were performed through a patternedfin-formation etch mask 107 to form a plurality of fin-formationtrenches 104 and thereby define a plurality of overall fin structures106. The width and height of the overall fin structures 106 may varydepending upon the particular application. Additionally, the overallsize, shape and configuration of the fin-formation trenches 104 andoverall fin structures 106 may vary depending on the particularapplication.

In the illustrative examples depicted in the attached drawings, thefin-formation trenches 104 and the fins 106 are all depicted as having auniform size and shape. However, such uniformity in the size and shapeof the trenches 104 and the fins 106 is not required to practice atleast some aspects of the inventions disclosed herein. In the attachedfigures, the fin-formation trenches 104 are depicted as having beenformed by performing an anisotropic etching process that results in theoverall fin structures 106 having a schematically (and simplistically)depicted, generally rectangular configuration. In an actual real-worlddevice, the sidewalls of the fins 106 may be somewhat outwardly tapered(i.e., the fins may be wider at the bottom of the fin than they are atthe top of the fin) although that configuration is not depicted in theattached drawings. Thus, the size and configuration of the trenches 104and the fins 106, and the manner in which they are made, should not beconsidered a limitation of the present invention. For ease ofdisclosure, only the substantially rectangular trenches 104 and fins 106will be depicted in the subsequent drawings. Moreover, the product 100may be formed with any desired number of fins 106. In the exampledepicted herein, the product 100 will be comprised of an NMOS device anda PMOS device, as depicted in FIG. 2B, each of which is comprised of twoof the illustrative fins 106 at this point in the process flow.

FIG. 2C depicts the product 100 after a layer of insulating material 108(e.g., silicon dioxide) was deposited so as to overfill thefin-formation trenches 104 and after at least one process operation,such as an optional CMP process, was performed to planarize the uppersurface of the layer of insulating material 108 and thereby expose theupper surface 106S of the fins 106. In some embodiments, rather thanremove the patterned mask layer 107 prior to the formation of the layerof insulating material 108, the layer of insulating material 108 may bedeposited so as to overfill the trenches 104 and the patterned masklayer. Thereafter, one or more CMP processes may be performed to removethe patterned mask layer 107 and portions of the layer of insulatingmaterial 108, stopping on the upper surface 106S of the fins 106.

FIG. 2D depicts the product 100 after a timed, recess etching processwas performed to remove a portion of the fins 106 for both of thedevices and to thereby define a plurality of replacement fin cavities110 above the remaining portions of the fins 106R, which will become thelower substrate portion of the completed fins for the two devices. Thedepth of the fin cavities 110 may vary depending upon the particularapplication. In general, the depth of the fin cavities 110 should beshallow enough such that a fully-strained, substantially defect freesemiconductor material 112 (described below) may be formed in the fincavities 110, e.g., about 30-50 nm. The semiconductor material 112 maybe comprised of a semiconductor material that is different from that ofthe substrate material 102. For example, if the substrate 102 is made ofsilicon, the semiconductor material 112 may be made of silicon germanium(Si_((1-x))Ge_(x) where “x” ranges from 0.1-1), such asSi_(0.75)Ge_(0.25) or Si_(0.50)Ge_(0.5), substantially pure germanium, aIII-V material, etc. The semiconductor material 112 may be formed byperforming an epitaxial growth process, and it may have a thickness thatcorresponds approximately to the depth of the fin cavities 110. As willbe appreciated by those skilled in the art after a complete reading ofthe present application, the semiconductor material 112 will become thechannel semiconductor material for the PMOS device.

FIG. 2E depicts the product 100 after the semiconductor material 112 wasformed on the recessed upper surface of the remaining portions of thefins 106R in the fin cavities 110 by performing an epitaxial depositionprocess. As noted above, in one illustrative embodiment, thesemiconductor material 112 may be a fully-strained, substantiallydefect-free substantially pure germanium material or a silicon-germaniummaterial. In one embodiment, the growth of the semiconductor material112 may be controlled such that it remains entirely within thereplacement fin cavities 110. In other embodiments, the semiconductormaterial 112 may be formed such that it overfills the replacement fincavities 110. In such a situation, a CMP process may be performed toremove excess amounts of the semiconductor material 112 positionedoutside of the replacement fin cavities 110. If desired, thesemiconductor material 112 may be formed with a compressive stress toenhance the performance of the PMOS device.

FIG. 2F depicts the product 100 after the layer of insulating material108 was recessed so as to expose all or a portion of the semiconductormaterial 112 above the recessed upper surface 108R of the layer ofinsulating material 108.

FIG. 2G depicts the product 100 after several process operations wereperformed. First, a masking layer 114, such as a patterned hard masklayer, was formed so as to cover the PMOS region and expose the NMOSregion for further processing. Then, a timed epitaxial growth processwas performed through the patterned masking layer 114 to form a layer ofsemiconductor material cladding 116 on the fins 106 for the NMOS device.In one illustrative embodiment, the semiconductor material cladding 116may have a thickness of about 1-6 nm. The semiconductor materialcladding 116 may be made of a semiconductor material that is differentthan that of the semiconductor material 112. In one illustrativeembodiment, where the semiconductor material 112 is comprised ofsilicon-germanium (Si_(0.75)Ge_(0.25) or Si_(0.50)Ge_(0.5)), thesemiconductor material cladding 116 may be a layer of silicon.

In another example, the semiconductor material 112 may be a SiGematerial and the semiconductor material cladding 116 may be a SiGematerial with a higher amount of germanium than is present in the SiGesemiconductor material 112. If desired, the semiconductor materialcladding 116 may be formed with a tensile stress to enhance theperformance of the NMOS device. As will be appreciated by those skilledin the art after a complete reading of the present application, thesemiconductor material cladding 116 will be the primary region where thechannel will form for the NMOS device during operation. As should beclear from the forgoing, in some embodiments, the semiconductor materialof the substrate 102 and the semiconductor material cladding 116 may bemade of the same semiconductor material, e.g., they both may be made ofsilicon. In other embodiments, the semiconductor material of thesubstrate 102, the semiconductor material 112 and the semiconductormaterial cladding 116 may each be made of different semiconductormaterials.

At the point of processing depicted in FIG. 2G, the masking layer 114may be removed and the illustrative FinFET-based CMOS product 100 may becompleted using traditional fabrication techniques. For example, FIG. 2Hdepicts the product, after illustrative and representative gatestructures 120 and gate cap layers 122 were formed for the NMOS and PMOSdevices. Of course, the materials of construction for the gatestructures of the NMOS and PMOS devices may be (and likely will be)different for the two different types of devices. In one illustrativeembodiment, the schematically depicted gate structures 120 include anillustrative gate insulation layer 120A and an illustrative gateelectrode 120B. The gate insulation layer 120A may be comprised of avariety of different materials, such as, for example, silicon dioxide, aso-called high-k (k greater than 10) insulation material (where k is therelative dielectric constant), etc. Similarly, the gate electrode 120Bmay also be of a material such as polysilicon or amorphous silicon, orit may be comprised of one or more metal layers that act as the gateelectrode 120B. As will be recognized by those skilled in the art aftera complete reading of the present application, the gate structures 120of the product 100 depicted in the drawings, i.e., the gate insulationlayer 120A and the gate electrode 120B, are intended to berepresentative in nature. That is, the gate structures 120 may becomprised of a variety of different materials and they may have avariety of configurations. The gate structures 120 may be manufacturedusing either the so-called “gate-first” or “replacement gate”techniques.

FIGS. 3A-3I depict yet other illustrative novel methods disclosed hereinfor forming PMOS FinFET devices and multiple NMOS FinFET devices withdifferent structural configurations and different performancecharacteristics on CMOS based integrated circuit products. In thisembodiment, the CMOS based integrated circuit product 100 comprises bothNMOS and PMOS transistors, but there are two different variations ortypes of NMOS devices. The selected NMOS FinFET device has a differentphysical configuration as compared to the other type of NMOS device soto as to enhance the performance capabilities of selected,performance-enhanced NMOS devices as compared to the other type of NMOSdevice. As used below, one of the NMOS devices will be referred to as aregular or standard NMOS device (with the designation NMOSR), whereasthe performance-enhanced type of NMOS device will be referred to withthe designation NMOSPE. As will be appreciated by those skilled in theart after a complete reading of the present application, the PMOS deviceand the two different types of NMOS devices may be formed at variouslocations across the substrate 102, i.e., they need not be formedlaterally adjacent to one another, although that configuration may beemployed in some applications. In the drawings that follow, each of thethree devices will be depicted as being comprised of a single fin.However, in practice, each of the devices may comprise any number offins and each of the devices need not have the same number of fins,although such a configuration may be employed in some applications.

FIG. 3A depicts the product 100 after a trench 132 was formed in thesubstrate 102 by performing an etching process through a patterned etchmask (not shown). In this embodiment, semiconductor material 134(described below) that will be used for the fins for both the PMOSdevice and the performance-enhanced NMOSPE device will be formed in thetrench 132. The depth and width of the trench 132 may vary dependingupon the particular application and the number of fins for each of thePMOS device and the performance-enhanced NMOSPE device.

FIG. 3B depicts the product 100 after a fully-strained, substantiallydefect-free semiconductor material 134 was formed in the trench 132 forboth the PMOS device and the performance-enhanced NMOSPE device. Thesemiconductor material 134 may be comprised of a semiconductor materialthat is different from that of the semiconductor material of thesubstrate 102. For example, if the substrate 102 is made of silicon, thesemiconductor material 134 may be made of silicon germanium(Si_((1-x))Ge_(x) where “x” ranges from 0.1-1), such asSi_(0.75)Ge_(0.25) or Si_(0.50)Ge_(0.5), substantially pure germanium, aIII-V material, etc. The semiconductor material 134 may be formed byperforming an epitaxial growth process and it may have a thickness thatcorresponds approximately to the depth of the trench 132. As will beappreciated by those skilled in the art after a complete reading of thepresent application, the semiconductor material 134 will become thechannel semiconductor material for the PMOS device

Of course, the single trench 132 depicted in FIG. 3A is but one exampleof a process flow that may be performed using the methods disclosedherein. That is, in practice, the semiconductor material(s) for the finsof the PMOS device and the performance-enhanced NMOSPE device may beformed in separate, laterally spaced apart trenches that are formed atvarious locations across the substrate 102 in an alternative processflow that is depicted in FIGS. 3C-3D. In this alternative flow, twophysically separated trenches 132A, 132B are defined in the substrate102. Of course, as noted above, if desired, the two physically separatedtrenches 132A, 132B may be filled with the same semiconductor material,e.g., the material 134, for both the PMOS device and theperformance-enhanced NMOSPE device. However, in one alternative processflow, different semiconductor materials 135, 137 will be formed in thetrenches 132A, 132B for the PMOS device and the performance-enhancedNMOSPE device, respectively. In general, each of the semiconductormaterials 135, 137 is a different semiconductor material than thesemiconductor material of the substrate 102. For example, in oneillustrative embodiment, the semiconductor material 135 may be afully-strained substantially pure germanium material that is formed witha compressive stress, while the semiconductor material 137 may becomprised of silicon-germanium (e.g., Si_(0.75)Ge_(0.25) orSi_(0.50)Ge_(0.5)). In one particular embodiment, where the substrate102 is made of silicon, the fins for the regular or standard NMOSRdevice, the PMOS device and the performance-enhanced NMOSPE device maybe comprised of silicon, a substantially pure germanium material andsilicon-germanium (e.g., Si_(0.75)Ge_(0.25) or Si_(0.50)Ge_(0.5)),respectfully. In the case where the semiconductor materials 135, 137 aremade of two different semiconductor materials, they may be formed byperforming different epitaxial growth processes while masking one of thetrenches 132A, 132B so as to fill the unmasked trench with the desiredsemiconductor material, e.g., 135 or 137. The manner in which such episemiconductor materials are formed so as to have a compressive stress ora tensile stress are well known to those skilled in the art. In thedrawings that follow, the embodiment shown in FIGS. 3A-3B will bedepicted. Of course, the following process flow would be equallyapplicable to the alternative process flow depicted in FIGS. 3C-3D.

FIG. 3E depicts the product 100 after several process operations wereperformed. First, one or more etching processes, e.g., anisotropicetching processes, were performed through a patterned fin-formation etchmask (not shown) to form a plurality of fin-formation trenches 104 andthereby define a plurality of overall fin structures 106A-C(collectively referred to using the number 106). The fins 106A, 106B and106C are, respectively, for the regular or standard NMOSR device, thePMOS device and the performance-enhanced NMOSPE device. As depicted, thefin 106A is comprised entirely of the substrate 102 semiconductormaterial, while, in this illustrative process flow, an upper portion ofthe fins 106B, 106C are comprised of the semiconductor material 134 anda lower substrate fin portion 106X. In the case of the alternativeprocess flow discussed above in FIGS. 3C-3D, the fin 106B would becomprised of the semiconductor material 135, while the fin 106C would becomprised of the semiconductor material 137. Next, the above-describedlayer of insulating material 108 (e.g., silicon dioxide) was depositedso as to overfill the fin-formation trenches 104 and a chemicalmechanical polishing (CMP) process was performed to planarize the uppersurface of the layer of insulating material 108 and thereby expose theupper surface of the fins 106.

FIG. 3F depicts the product 100 after the layer of insulating material108 was recessed so as to expose all or a portion of the semiconductormaterial 134 of the fins 106B, 106C above the recessed upper surface108R of the layer of insulating material 108.

FIG. 3G depicts the product 100 after a masking layer 136, such as apatterned hard mask layer, was formed so as to cover the regular NMOSRdevice and the PMOS device while leaving the performance-enhanced NMOSPEdevice exposed for further processing.

FIG. 3H depicts the product 100 after a timed, epitaxial growth processwas performed through the patterned masking layer 136 to form theabove-described layer of semiconductor material cladding 116 on the fin106C for the performance-enhanced NMOSPE device. As will be appreciatedby those skilled in the art after a complete reading of the presentapplication, the semiconductor material cladding 116 will be the primaryregion where the channel will form for the performance-enhanced NMOSdevice during operation. The semiconductor material cladding 116 may bemade of a semiconductor material that is different than that of thesemiconductor material 134 (or different from that of the semiconductormaterial 137 in the alternative process flow described above). In oneillustrative embodiment, where the semiconductor material 134 iscomprised of silicon-germanium (Si_(0.75)Ge_(0.25) orSi_(0.50)Ge_(0.5)), the semiconductor material cladding 116 may be alayer of silicon. If desired, the semiconductor material cladding 116may be formed with a tensile stress to enhance the performance of theperformance-enhanced NMOSPE device. As should be clear from theforgoing, in some embodiments, the semiconductor material of thesubstrate 102 and the semiconductor material cladding 116 may be made ofthe same semiconductor material, e.g., they both may be made of silicon.In other embodiments, the semiconductor material of the substrate 102,the semiconductor material 134 (and 135, 137 if they are present) andthe semiconductor material cladding 116 may each be made of differentsemiconductor materials.

Forming the semiconductor material cladding 116 on theperformance-enhanced NMOSPE device may increase its performance (e.g.,the performance-enhanced NMOSPE device may exhibit greater drive currentcapabilities as well as other device characteristics relative to aregular or standard NMOSR device. Typically, the regular NMOSR devicecomprises a relaxed semiconductor material which tends to reduce itsperformance capabilities. The cladding 116 on the NMOSPE device is astrained material that should enhance the performance characteristics ofthe NMOSPE device relative to a regular NMOSR device. In addition, theclad NMOSPE device is a quantized device (it is a quantum well region)which will also help the performance of the NMOSPE device. These devicesconstitute a 2D electron gas system and the performance of the deviceswould be superior as compared to devices made from regular bulkmaterials, e.g., higher drive currents at lower voltage, lower leakageat the corresponding voltage, etc. Producing a CMOS based integratedcircuit product 100 with the two different “grades” of NMOS devicesprovides device designers with greater flexibility when designing CMOSbased integrated circuit products manufactured using FinFET devices. Ina typical integrated circuit product, there are needs for devices withdifferent operational characteristics, e.g., high-performance,high-power devices; low-performance, low-power devices, etc., that havedifferent threshold voltages. The methods and devices disclosed hereinprovide product designers more design flexibility by providing NMOSR,NMOSPE and PMOS devices which have different performancecharacteristics, thereby enabling the product designer to more preciselydesign the desired integrated circuit product such that it meets allperformance specifications established for the IC product.

At the point of processing depicted in FIG. 3H, the masking layer 136may be removed and the illustrative FinFET-based CMOS product 100 may becompleted using traditional fabrication techniques. For example, FIG. 3Idepicts the product 100 after the above-described illustrative andrepresentative gate structures 120 and gate cap layers 122 were formedfor the regular NMOSR device, the PMOS device and theperformance-enhanced NMOSPE device. Of course, the materials ofconstruction for the gate structures of the NMOS and PMOS devices may be(and likely will be) different, i.e., different work function metals areused for the NMOS and PMOS devices.

The particular embodiments disclosed above are illustrative only, as theinvention may be modified and practiced in different but equivalentmanners apparent to those skilled in the art having the benefit of theteachings herein. For example, the process steps set forth above may beperformed in a different order. Furthermore, no limitations are intendedto the details of construction or design herein shown, other than asdescribed in the claims below. It is therefore evident that theparticular embodiments disclosed above may be altered or modified andall such variations are considered within the scope and spirit of theinvention. Note that the use of terms, such as “first,” “second,”“third” or “fourth” to describe various processes or structures in thisspecification and in the attached claims is only used as a shorthandreference to such steps/structures and does not necessarily imply thatsuch steps/structures are performed/formed in that ordered sequence. Ofcourse, depending upon the exact claim language, an ordered sequence ofsuch processes may or may not be required. Accordingly, the protectionsought herein is as set forth in the claims below.

1. A method of forming PMOS and NMOS FinFET devices for a CMOSintegrated circuit product formed on a semiconductor substrate made of afirst semiconductor material, the method comprising: forming a first finfor said PMOS device and a second fin for said NMOS device, each of saidfirst and second fins comprising a lower substrate fin portion made ofsaid first semiconductor material and an upper fin portion that ispositioned above said lower substrate fin portion, wherein said upperfin portion of said first and second fins is made of a semiconductormaterial that is different from said first semiconductor material;performing at least one process operation to form a recessed layer ofinsulating material adjacent said first and second fins, said recessedlayer of insulating material comprising a recessed upper surface thatexposes at least a portion of said upper fin portion of both of saidfirst and second fins; forming a first patterned masking layer thatcovers said PMOS device and exposes said NMOS device; with said firstpatterned masking layer in position, performing an epitaxial depositionprocess to form a semiconductor material cladding on said exposed upperportion of said second fin for said NMOS device, wherein saidsemiconductor material cladding is a different semiconductor materialthan that of said semiconductor material of said upper fin portion ofsaid second fin; forming a PMOS gate structure for said PMOS FinFETdevice around said exposed upper portion of said first fin of said PMOSdevice; and forming an NMOS gate structure for said NMOS FinFET devicearound said semiconductor material cladding.
 2. The method of claim 1,wherein said first semiconductor material is silicon, said semiconductormaterial of said upper fin portions of said first and second finscomprises silicon-germanium (Si_((1-x))Ge_(x) where “x” ranges from0.1-1), substantially pure germanium, or a III-V material, and saidsemiconductor material cladding comprises silicon-germanium(Si_((1-x))Ge_(x) where “x” ranges from 0.1-1) or silicon.
 3. The methodof claim 1, wherein said first semiconductor material is silicon, saidsemiconductor material of said upper fin portions of said first andsecond fins comprises silicon-germanium (Si_((1-x))Ge_(x) where “x”ranges from 0.1-1), and said semiconductor material cladding is silicon.4. The method of claim 1, wherein said first semiconductor material issilicon, said semiconductor material of said upper fin portions of saidfirst and second fins is silicon-germanium and said semiconductormaterial cladding is silicon-germanium with a germanium concentrationthat is greater than a germanium concentration of said semiconductormaterial of said fin upper portions of said first and second fins. 5.The method of claim 1, wherein said semiconductor material of said upperfin portions of said first and second fins is formed with a compressivestress.
 6. The method of claim 5, wherein said semiconductor materialcladding is formed with a tensile stress.
 7. The method of claim 1,wherein said first semiconductor material and said semiconductormaterial cladding are made of a same semiconductor material.
 8. Themethod of claim 1, wherein said first semiconductor material, saidsemiconductor material of said upper fin portions of said first andsecond fins, and said semiconductor material cladding are each differentsemiconductor materials.
 9. The method of claim 1, wherein performingsaid epitaxial deposition process to form said semiconductor materialcladding comprises performing said epitaxial deposition process to forma conformal layer of said semiconductor material cladding having asubstantially uniform thickness on said exposed upper portion of saidsecond fin for said NMOS device.
 10. (canceled)
 11. A method of formingPMOS and NMOS FinFET devices for a CMOS integrated circuit productformed on a semiconductor substrate made of a first semiconductormaterial, the method comprising: forming a first fin for said PMOSdevice and a second fin for said NMOS device, each of said first andsecond fins comprising said first semiconductor material; forming alayer of insulating material in a plurality of fin-formation trenchesdefined in said substrate adjacent said first and second fins;performing a first common recess etching process on both said first andsecond fins to define a first recessed fin with a first recessed fincavity located above said first recessed fin and a second recessed finwith a second recessed fin cavity located above said second recessedfin; performing a first epitaxial deposition process to form a secondsemiconductor material in said first and second fin cavities on saidrecessed first and second fins, wherein said second semiconductormaterial is a semiconductor material that is different from said firstsemiconductor material; performing at least one recess etching processon said layer of insulating material to expose at least a portion ofsaid second semiconductor material above both of said recessed first andsecond fins; forming a first patterned masking layer that covers saidPMOS device and exposes said NMOS device; with said first patternedmasking layer in position, performing a second epitaxial depositionprocess to form semiconductor material cladding on said exposed portionof said second semiconductor material above said recessed second fin forsaid NMOS device, wherein said semiconductor material cladding is adifferent semiconductor material than said second semiconductormaterial; forming a PMOS gate structure for said PMOS FinFET devicearound said exposed portion of said second semiconductor material abovesaid recessed first fin of said PMOS device; and forming an NMOS gatestructure for said NMOS FinFET device around said semiconductor materialcladding.
 12. The method of claim 11, wherein said first semiconductormaterial is silicon, said second semiconductor material comprisessilicon-germanium (Si_((1-x))Ge_(x) where “x” ranges from 0.1-1),substantially pure germanium, or a III-V material and said semiconductormaterial cladding comprises (Si_((1-x))Ge_(x) where “x” ranges from0.1-1) or silicon.
 13. The method of claim 11, wherein said firstsemiconductor material is silicon, said second semiconductor materialcomprises silicon-germanium (Si_((1-x))Ge_(x) where “x” ranges from0.1-1), and said semiconductor material cladding is silicon.
 14. Themethod of claim 11, wherein said first semiconductor material issilicon, said second semiconductor material is silicon-germanium with afirst germanium concentration and said semiconductor material claddingis silicon-germanium with a second germanium concentration that isgreater than said first germanium concentration
 15. The method of claim11, wherein said second semiconductor material is formed with acompressive stress.
 16. The method of claim 15, wherein saidsemiconductor material cladding is formed with a tensile stress.
 17. Themethod of claim 11, wherein said first semiconductor material and saidsemiconductor material cladding are made of a same semiconductormaterial.
 18. The method of claim 11, wherein said first semiconductormaterial, said second semiconductor material and said semiconductormaterial cladding are each different semiconductor materials.
 19. Themethod of claim 11, wherein performing said second epitaxial depositionprocess to form said semiconductor material cladding comprisesperforming said second epitaxial deposition process to form a conformallayer of said semiconductor material cladding having a substantiallyuniform thickness on said exposed upper portion of said second fin forsaid NMOS device.
 20. The method of claim 1, wherein upper fin portionof said first fin is made of a second semiconductor material and saidupper fin portion of said second fin is made of a third semiconductormaterial that is different from said second semiconductor material. 21.The method of claim 1, wherein forming said first and second finscomprises: forming first and second laterally spaced apart trenches insaid semiconductor substrate; filling said first trench with a secondsemiconductor material; filing said second trench with a thirdsemiconductor material that is different from said second semiconductormaterial; and performing at least one etching process through apatterned fin-formation mask to define said first and second fins,wherein said upper fin portion of said first fin is made of said secondsemiconductor material and said upper fin portion of said second fin ismade of said third semiconductor material.